Effect of benzodiazepine on temporal integration in object perception

Rationale: Though various psychometrical tests indicate that benzodiazepines affect vigilance, few studies have been conducted to assess the effect of benzodiazepines on attentional processes. Objective: We used a RSVP (Rapid Serial Visual Presentation) procedure to investigate the effect of benzodiazepines on the attentional blink effect. It refers to the difficulty in detecting a probe following identification of a target within a temporal window of 500 ms. Method: Three experimental groups were tested (placebo, lorazepam and diazepam). Sequences of 15 pictures were centrally displayed for 50 ms each. In a dual-task condition, observers were instructed (1) to identify the target (the single picture on a blue background) and (2) to detect the presence of a probe. In the single-task condition, subjects were asked to detect the probe. The serial position of the probe relative to the target was varied. Results: Performance was equivalent for the three groups in the single task condition. In the dual-task condition, the attentional blink was increased in magnitude and duration for benzodiazepine-treated subjects, especially diazepam, than fur placebo-treated subjects. A large number of intrusions (a tendency to report as target the name of a picture preceding the target) were observed in the benzodiazepine-treated groups. Conclusion: The results indicate that benzodiazepines impair visual integration in the temporal domain. This extends previous findings that benzodiazepine impairs visual integration in the spatial domain. The results also suggest that benzodiazepine increase time to disengage attention from a first to a second target.